Hi Tom and Robert, 

I added a mechanism to fall back to v3.0 if the BE fails to start when FE 
initiates a connection with v3.1 (with optional startup parameters). This 
completely eliminates the need to backpatch older servers, ie newer FE can 
connect to older BE. Please let me know what you think.


-----Original Message-----
From: Robert Haas [mailto:robertmh...@gmail.com] 
Sent: Wednesday, October 4, 2017 4:54 AM
To: Tom Lane <t...@sss.pgh.pa.us>
Cc: Badrul Chowdhury <bac...@microsoft.com>; Satyanarayana Narlapuram 
<satyanarayana.narlapu...@microsoft.com>; Craig Ringer <cr...@2ndquadrant.com>; 
Peter Eisentraut <pete...@gmx.net>; Magnus Hagander <mag...@hagander.net>; 
PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] Re: protocol version negotiation (Re: Libpq 
PGRES_COPY_BOTH - version compatibility)

On Tue, Oct 3, 2017 at 9:46 PM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> Badrul Chowdhury <bac...@microsoft.com> writes:
>> 1. Pgwire protocol v3.0 with negotiation is called v3.1.
>> 2. There are 2 patches for the change: a BE-specific patch that will be 
>> backported and a FE-specific patch that is only for pg10 and above.
> TBH, anything that presupposes a backported change in the backend is 
> broken by definition.  We expect libpq to be able to connect to older 
> servers, and that has to include servers that didn't get this memo.
> It would be all right for libpq to make a second connection attempt if 
> its first one fails, as we did in the 2.0 -> 3.0 change.

Hmm, that's another approach, but I prefer the one advocated by Tom Lane.


Robert Haas
The Enterprise PostgreSQL Company

Attachment: pgwire3.1.patch
Description: pgwire3.1.patch

Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:

Reply via email to